The present invention relates to computer systems, in particular to multiprocessor systems, for example multiprocessor server systems.
One application for the present invention relates to high density computer systems, for example, computer server systems for telecommunications applications. In telecommunications applications, it is important to provide high reliability and high capacity of operation. Various approaches have been taken to providing such high-performance, high reliability systems. Typically such systems are designed around providing redundant resources so that if one component of the system develops a fault, the system remains operational using the redundant resources. Fault tolerance can also be achieved, for example, with multiprocessor systems that provide redundancy through dynamic, e.g., software-controlled, task distribution. High density systems are typically rack mountable, with one or more processor systems occupying a shelf in the rack. The trend in recent times is to make the computers with smaller form factors. This means that more computers can be located in a rack. This has the advantage of increasing the processing density within the racks, and also the advantage of reducing the distance between the computer systems.
One cause of component failure in computer systems is overheating of components. Overheating of components may cause intermittent temporary or permanent failures. Such failures are incompatible with the requirement for a computer to have a minimum downtime. Therefore, fans are regularly used to provide cooling within a computer system by drawing or pushing cool (usually ambient temperature) air through the computer system to move air heated by virtue of being adjacent components to be replaced with cool air to provide a better temperature gradient for transfer of heat from the components to the air.
It is usual to control cooling airflow within computer systems such that cooling air is drawn in through the front of the housing or enclosure and is ejected through the rear or vice versa. In computer systems where active modules are inserted to both the front and rear of a housing or enclosure, this brings a problem that air reaching downstream components is preheated by upstream components. Taking the example of a front to rear cooling air flow, all the air drawn in through the front modules is heated by the front-mounted modules before passing through the housing to the rear-mounted modules. Thus cooling air reaching the rear-mounted modules is provides less cooling effect to those rear-mounted modules than was provided to the front-mounted modules.
An aspect of the invention provides an enclosure for a modular computer system. The enclosure can include a first face with one or more first module receiving locations for receiving one or more removable first computer system modules and a second face with one or more second module receiving locations for receiving one or more removable second computer system modules. One or more openings can be provided in the first face. One or more passages can define a flow path for cooling air between the opening(s) and the second module receiving location(s), which flow path bypasses the first module receiving location(s).
The provision of a passage, which can be in the form of a plenum chamber can enable a compact arrangement of computer system modules to be provided with some modules behind others and with cooling air being supplied to heat sensitive modules without passing through other modules that may generate heat.
If one or more further module receiving locations are provided in the second face for receiving one or more removable third computer system module, a separate flow path from that described above may be provided. For example, a further passage may be defined for a further flow path if the further module is heat sensitive. Alternatively, if the further module is not particularly sensitive, the space required for a further passage can be saved and the further flow path can pass via the first module receiving location(s) and the further module receiving location(s).
Another aspect of the invention provides a modular computer system including an enclosure as described above, one or more removable first computer system module received at the first module receiving location(s) and arranged to be cooled by flow of air therethrough, and one or more removable second computer system module received at the second module receiving location(s) and arranged to be cooled by a flow of air therethrough.
Another aspect of the invention provides a high density server system comprising an enclosure for receiving computer system modules, wherein: a plurality of information processing modules are receivable at a first face of the enclosure; a plurality of first support modules are receivable at a second face of the enclosure; a plurality of second support modules are receivable at the second face of the enclosure; and the enclosure includes a plenum chamber to provide a flow path for air for cooling received first support modules to bypass received information processing modules.
A further aspect of the invention provides a method of cooling a high density server system comprising an enclosure for receiving computer system modules, wherein a plurality of information processing modules are receivable at a first face of the enclosure, a plurality of first support modules are receivable at a second face of the enclosure and a plurality of second support modules are receivable at the second face of the enclosure, the method comprising: installing the information processing modules, the first support modules and the second support modules; and supplying cooling air to received first support modules by drawing air along a flow path that includes a plenum chamber bypassing received information processing modules.
Further aspects and advantages of the invention will become apparent from the following description of particular embodiments.